This invention relates generally to ring binder mechanisms (broadly referred to herein as a ring mechanism) for retaining loose-leaf pages, and in particular to such a ring mechanism capable of opening and closing mating ring members and locking the ring members when closed.
A ring mechanism is typically used to retain loose-leaf pages, such as hole-punched pages, in a file or notebook. Ring mechanisms commonly have mating ring members that may be selectively opened to add or remove pages, or closed together to retain pages while allowing the pages to be moved along the ring members. The ring members mount on two adjacent (e.g., side-by-side) hinge plates that join together along a hinge line to form a pivot axis about which the plates may pivot. An elongate, resilient housing loosely supports the hinge plates within the housing and holds the hinge plates together so they may pivot relative to the housing.
The housing is slightly narrower than the joined hinge plates when the hinge plates are in a coplanar position (180°). In this manner, as the hinge plates pivot through their coplanar position, they deform the resilient housing and cause a spring force in the housing that urges the hinge plates to pivot away from the coplanar position, either opening or closing the ring members. Thus, when the ring members are closed the spring force resists hinge plate movement and clamps the ring members together. Similarly, when the ring members are open, the spring force holds them apart. An operator may typically overcome this force by manually pulling the ring members apart or pushing them together. Levers or other actuating systems may also be provided on one or both ends of the housing for moving the ring members between the open and closed positions. In some ring mechanisms, however, when the ring members are closed they do not positively lock in their closed position. As a result, if the mechanism is accidentally dropped, the ring members may unintentionally open.
To this end, some ring mechanisms have been modified to include locking structure to block the hinge plates from pivoting when the ring members are closed. The locking structure positively locks the closed ring members together, preventing them from unintentionally opening if the ring mechanism is accidentally dropped. The locking structure also allows the housing spring force to be reduced because the strong spring force is not required to clamp the closed ring members together. Thus, less operator force is required to open and close the ring members than in traditional ring mechanisms.
Some of these ring mechanisms incorporate the locking structure onto a control slide connected to the lever. The lever moves the control slide (and its locking structure) to either block the pivoting movement of the hinge plates or allow it. However, an operator must positively move the lever after closing the ring members to position the locking structure to block the hinge plates and lock the ring members closed. Failure to do this could allow the hinge plates to inadvertently pivot and open the ring members, especially if the mechanisms are accidentally dropped.
Other locking ring mechanisms use springs to move the locking structure into position blocking the hinge plates when the ring members close. Examples are shown in co-owned U.S. patent application Ser. Nos. 10/870,801 (Cheng et al.), Ser. No. 10/905,606 (Cheng), and Ser. No. 11/027,550 (Cheng). These mechanisms employ separate springs to help lock the mechanisms.
Accordingly, there is a need for a simple ring binder mechanism that readily locks ring members together when the mechanism is closed without requiring additional spring components to do so.
Moreover, the configuration of some locking ring binder mechanisms is such that the control slide can bind when the mechanism is being operated, which makes it difficult to open the rings of the mechanism. Accordingly, there is also a need for ring binder mechanisms in which such binding of the control slide is avoided.